Low-density lipoprotein metabolism in the nephrotic syndrome.
Hyperlipidemia is a consistent feature of the nephrotic syndrome. In this study, low-density lipoprotein (LDL) metabolism has been investigated in nine patients with nephrotic syndrome and varying degrees of proteinuria. In subjects with moderate proteinuria (less than 10 g/d), total plasma cholesterol values were elevated to approximately 160% of normal due mainly to an increase in circulating LDL cholesterol. Metabolic studies showed that a defect in LDL clearance via the receptor pathway was responsible for its accumulation. The total amount of LDL apolipoprotein catabolized by this mechanism was only 55% of the value seen in controls; 60% more LDL was channelled into alternative, receptor-independent, catabolic pathways. Heavier proteinuria was associated with substantial increases in plasma triglyceride and very-low-density lipoprotein (VLDL) levels. The defect in LDL catabolism was aggravated by oversynthesis of the lipoprotein, which expanded the plasma LDL pool to 250% of normal. These observations indicate that the hyperlipidemia of the nephrotic syndrome is multifactorial in origin. The altered catabolism of LDL may be important in predisposing these subjects to premature atherosclerosis.
Warwick
G L
GL
Department of Pathological Biochemistry, Glasgow Royal Infirmary, United Kingdom.
Caslake
M J
MJ
Boulton-Jones
J M
JM
Dagen
M
M
Packard
C J
CJ
Shepherd
J
J
D000328:Adult; D000368:Aged; D002318:Cardiovascular Diseases / Q000209:etiology; D002784:Cholesterol / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000209:etiology / Q000378:metabolism; D007700:Kinetics; D008077:Lipoproteins, LDL / Q000096:biosynthesis / Q000378:metabolism*; D008079:Lipoproteins, VLDL / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009404:Nephrotic Syndrome / Q000150:complications / Q000378:metabolism*; D011507:Proteinuria / Q000097:blood / Q000652:urine; D012306:Risk; D014280:Triglycerides / Q000097:blood
D008078:Cholesterol, LDL; D008077:Lipoproteins, LDL; D008079:Lipoproteins, VLDL; D014280:Triglycerides; D002784:Cholesterol